traffic txz is a zipped file containing drive indicators for hdd, usb, optical, and card-slots. There is a Read1st text that should be viewed before installation.
s57-2015a iso is an update to the 'non-a' version. This distro is intended for eeepc's of the 700 and 900 series, and the 100x series ONLY. Many non-eee drivers are removed to trim the size. Privacy settings in Firefox-27 have been tweaked, and openssl 1.0.1k is installed with the DOC files removed. This 'a' version includes the traffic-light drive indicators. A few more backgrounds are added, some that 'went binary' removed. There is a separate md5Notes file that indicates md5sum, and explains the traffic-lights. Compared to the 'non-a' version, this distro weighs in at 143.2 Mb compared to 152.0Mb.